If the electricity network is faulty and there are frequent power fluctuations, you can secure your hard disk by installing a special uninterruptible power supply unit. It is also advised that you copy crucial information to another carrier (DVD, CD etc.). After doing that you can rest assured that your data is safe, like you can be confident in successful work on currency stock exchange if you follow, study and analyze financial market news and adhere to the direction of its development.
Now about hackers and viruses. You should not forget that hackers are very advanced people in terms of technologies and related stuff, and there is no limit to their ingenuity. Viruses developed by hackers can destruct and infect all information on your hard drive or damage a part of it. So what is the way out? You can secure yourself from viruses by installing antivirus and regularly updating it. A probability of security and safety of your data in case you have a good and up-to-date antivirus increases manifold.
Another way of avoiding unnecessary damages to hard disk is to defragment your hard drive disk regularly. By doing that, your data will regroup in such a way that the speed of hard drive and chances of data recovery will rapidly rise. Please be careful when you work with different tools/utilities, and make sure that they are fully compatible with your operating system.
Only by following and adhering to the above tips you will get a positive and productive work from your computer and hard drive, just like the work of forex market. A work can be successful only if specific knowledge is correctly applied in practice. Even when the worst happens and you loose your data, first thing you should do is to contact a professional in the field of data recovery. Good luck!